Antibiotics have no effect on which type of pathogen?

• A. Virus
• B. Bacteria
• C. Parasite
• D. Fungus

Answer: (A)

Antibiotics target features unique to bacterial cells, such as cell wall construction, bacterial ribosomes, or specific bacterial enzymes. Viruses, on the other hand, don’t have their own ribosomes or cell walls and replicate by hijacking the host cell’s machinery inside living cells. Because there’s no bacterial target to hit, standard antibiotics don’t affect viruses. That’s why viral infections don’t improve with antibiotics; antiviral drugs or supportive care are used instead. For fungi or parasites, different drugs are used that target features specific to those organisms, so antibiotics aren’t effective there either. The bottom line is: antibiotics work on bacteria, not on viruses.